An object of the present invention is to provide a protective composition for gastrointestinal mucosa, for example, for inhibiting occurrence of a gastrointestinal mucosa disorder when an oral drug that induces the gastrointestinal mucosa disorder is taken. The protective composition for gastrointestinal mucosa of the present invention as a resolution for achieving the object is characterized by comprising at least a macromolecular polysaccharide, sodium hydrogen carbonate and/or magnesium carbonate, and a polyhydric alcohol. According to the protective composition for gastrointestinal mucosa of the present invention, sodium hydrogen carbonate or magnesium carbonate foams through contact with a gastric juice in stomach to thereby generate diffusing power for the macromolecular polysaccharide. This power can allow the macromolecular polysaccharide to quickly dissolve or disperse in the gastric juice and allow the macromolecular polysaccharide to effectively exert a gastric mucosa protective action. In addition, the macromolecular polysaccharide dissolved or dispersed in the gastric juice moves into intestine without degradation in stomach, then dissolves in an intestinal juice having a neutral or alkaline pH, and exerts an intestinal mucosa protective action without degradation also in intestine. The polyhydric alcohol plays a role as a dispersion medium for the macromolecular polysaccharide and sodium hydrogen carbonate or magnesium carbonate which are powder, or enables formulation of the protective composition for gastrointestinal mucosa of the present invention into various dosage forms, according to the nature and use amount thereof.